Etching machine



4 Sheets-Sheet 1 INVENTORS. Robert CI Benton EN wm mm EL Nm Dav/d A. Bouc/:spies THE /R A TTORNE YS March 26, 1963 R. c. BENTON ETAL ETCHING MACHINE Filed Feb. 8, 1961 rlllllllllllllllilllnll March 26, 1963 R. c. BENTON E'rAl. 3,082,774

ETCHING MACHINE Filed Feb. 8, 1961 4 Sheets-Sheet 2 4JAIVENTORS. Rober! @Eenrum Dawd A. Bauc/7spls's4 T HE ll'? ATTORNEYS March 26, 1963 R. c. BENTON ETAL 3,082,774

ETCHING MACHINE Filed Feb. '8, 1961 Y 4 sheets-sheet s INVENTORS. Rober! C. Benton F 7 BY David A. Bauens/ies THE IR A 7 TORNE YS March 26, 1963 R. c. BENTON ETAL 3,082,774

ETCHING MACHINE Filed Feb. 8, 1961 4 Sheets-Sheet 4 "l :I o /bllll Olmi-.q

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INVENTORS. Robert C. Benton David A. auchsples THE IR A T TORNE YS thee 3,082,774 ETCHING MACHINE Robert C. Benton and David A. Bauchspies, State College, Pa., assignors to Centre Cu'cuits, Inc., State College, Pa., a corporation of Pennsylvania Filed Feb. 8, 1961, Ser. No. 87,861 4 Claims. (Cl. 134-63) The present application relates to a machine for spray etching parts such as thin metal Webs or panels, and also metal clad panels. More particularly, it relates to a horizontal roller table structure for conveying parts being processed through the machine.

Articles in the category of thin metal webs and other parts suitable to be conveyed through and processed by etching machines include electric motor laminations, television masks, intricate flat spring steel parts, transformer laminations, and microwave attenuators, each being provided with exposed areas and acid resist masked areas. The etchant `fluid forms perforations in the exposed areas only. The metal clad panels referred to are predominantly printed `circuit boards, these boards generally having both sides provided with metal cladding on a flat backing, usually an insulative panel. An -acid resist pattern on the metal preserves the metal circuit portions which are -to be retained on the insulative panel.

It is found in practice that spray etching work -is more uniformly done in many cases with the work in a horizontal position rather than in a vertical plane. Even so, etchant tends to attack the topside surface and the underside surface of the work at a different rate, with the underside being .etched faster. The chief reason is that inactive etchant collects and stands in a topSide layer, which must always preliminarily be scrubbed away by the oncoming sprays, whereas the etchant drips naturally from the underside surface so as to rapidly re-expose it unimpededly to the lowermost sprays. Also, to mention another of the reasons, it is noted that the static head on the lowermost sprays is slightly higher giving their droplets slightly higher velocity of impingement than the uppermost sprays produce at their elevation.

The present horizontal conveyor is provided with a plurality of rollers to overcome the above difference in inequality. Proper roller distribution in accordance with this invention tends to balance the rates of etching by blanking of portions of the underside surface of the panels. Moreover, no racks are necessary where the articles processed are individual panels, being as the roller distribution provides a plurality of supporting points on which the articles readily ride irrespective of whether the series of articles is formed in a continuous web or else separated as individual articles. Live axles are provided for carrying these rollers in rows, and the axles establish a separate fixed axis of rotation for each such row.

A feature of this conveyor is the incorporation therein of novel iiuid traps at its points of entry and exit from each spray compartment or chamber of the spray etching machine. These traps prevent carry-over of etchant liquid or rinse liquid between chambers and also prevent escape of the liuids beyond the outermost chambers.

As above indicated, an etching machine embodying the present conveyor is primarily adapted for the handling and processing of webs or panels presenting metal surfaces on both sides. It -is understood according to the broader principles hereof that the invention will effectively etch single-sided work, i.e., a panel or web presenting metal to be etched at one side only.

Further features, objects and advantages are either specifically pointed out or ywill become apparent when, for a better understanding of the invention, reference is made to the following written description taken in conjunction vwith the accompanying drawings in which:

FIGURES l and 2 are longitudinal side elevational and top plan views, respectively, of `an etcher with a conveyer therein embodying the present invention;

FIGURE 3 is a fragmentary portion of FIGURE 2 drawn to enlarged scale;

FIGURE 4 is a transverse elevational view taken along the lines IV-IV of FIGURE l;

FIGURE 5 is a longitudinal view in side elevatio taken along the lines V-V of FIGURE 4;

FIGURES 6 and 7 are elevational views transversely and longitudinally, respectively, taken along the section lines VI--VI and VII-VII of FIGURE 2; and

FIGURE 8 is a fragmentary showing in side elevation of a ldouble tiered modification of the conveyor invention of FIGURE 1. i

More particularly, in FIGURES l and 2 of the drawings, a spray etching machine is shown having a base 1i) which by means of a set of upright pillars 12 and l14- supports a loading station 16 at one end onto which incoming articles 18a are placed. By means of upright pillars 20 and 22 thereon, the base 1? provides an unloading station at the other end consisting of a receiving tray 24 for the etched articles 18h being discharged.

Intermediate the end loading station 16 and the end unloading station, a series of tandem connected spray chambers is located on the base 1d consisting of a main etchant chamber 26, a iirst rinse chamber 2.8 and a final rinse chamber 30. Two side guide panels 32 joined by a cover .34 at the top Iform an entry housing on the entry side of the etchant chamber 26. Four traps 36 are provided, one at a location in the entry wall of the chamber 2.6 in alignment with the housing 34, `another in a division wall 38 between the chambers 26 and 28, another in a division wall 39 .between the chambers 28 and 30, and the last trap 36 in the exit wall 40' of the chamber 36. These traps actually constitute a rotary battle system which operates so that spray and fume carry-out is minimized.

A motor-operated roller table 42 extending in a horizontal plane between the end loading station 16 and the end unloading station conveys the articles from the position 18a through the series of chambers to the discharge position 18b. A continuously running, external drive motor 44 is connected through a pinion and gear drive 46 to operate the 4individual rollers 48 of the roller table 42. The motor 44 is supported by a cross member carried between the uprights 12 and 14.

Turning of the rollers 4S in the proper direction on their iixed axes causes articles on the conveyor 42 to move in a horizontal path from left to right as viewed in FIG- URES l and 2. Within chamber 26, these articles pass between groups of spray nozzles, the lowerrnost ones 50 of which are directed transversely upwardly so as to discharge in the plane of the conveyor 42. The uppermost nozzles 52 discharge downwardly in a transverse direction to the horizontal path of movement of the articles. These groups of nozzles are supplied from the outlet 54 from one or more recirculating pumps 56 and leading through connections, not shown, to the manifolds for the nozzles. Each pump 56 has a suction line 5S and is driven from a pedestal mounted motor 60 all as more completely shown and described in Bauchspies application, Serial No. 6,899, filed February 5, 1960, and now abandoned. Preferably, two of the motor-driven pumps S6 are employed as shown in a plan view of FIGURE 2, enabling the uppermost nozzles 52 to have a separately controllable source of supply from the source of the lowermost nozzles 50, 4in case single-sided work is to be processed.

The etchant iiuid supply 62 collected in the bottom of the chamber 26 is continually replenished by recovering7 spray from the nozzles which is then recirculated. A heater 6 keeps the supply of etchant at the proper temperature. If copper is `the metal being etched from the articles, one suitable etchant solution is ferric chloride.

A water rinse recirculation system within the chamber 28 consists of spray nozzles 66 and 68 above and below the horizontal path of the conveyor 42 and a pump circulation system, not shown, including a pump suction line 70 whereby pressure induced sprays are forced through the nozzles 66 and 68. The final rinse chamber 30 contained similar nozzles 72 and 74, along with a separate pump system, not shown, including a pump suction line In FIGURES 3, 4 and 5, the horizontal conveyor table 4Z provided with rows of the rollers 48 has full length walking `beams 78 and 80 disposed one on each side. The walking beams 78 and 80 are supported at each end by common cross shafts, one of which is shown at 82a in FIGURE 3 and each carrying a crank 84 at each end with the throw journaled in a hole in the walking beam at that end. As viewed along the axis of the shaft 82a, the cranks 84 are offset or phased at 90 angularity to one another to insure unidirectional movement of the ybeams in a curved path; one or more intermediate cross shafts 82h are provided to furnish intermediate support for the -walking beams 78 and 80, and they carry similarly phased cranks 84.

The pinion and gear connection 46 `from the drive motor 44 rotates the shaft 82a whose cranks 84 force vthe walking beams 78 and 80 each to move in a path closing on itself and circular in nature as indicated in FIGURE 5. An arrow is used to indicate the resulting direction of material movement in FIGURES 3, 5, and other figures of the drawings. Roller carrying shafts 86 have cranks 88 provided at one end only `and connected to the walking beam 78 at that end so that the shafts 82a, 82h and 86 rotate in unison; the throw of the cranks 86 has the same phase angularity land throw as the cranks 84 journaled in the walking beam 78. These shafts `form live axles for the rollers and have fixed center to center distances M which exceed the individual roller diameters and which are established by equally spaced shaft bearing holes provided in a pair of stationary bearing bars 90. The shafts thus space the rollers 48 apart so that the rows do not overlap in the longitudinal direction, and in the transverse direction, the rollers 48 of the row of rollers on each shaft 86 are equally spaced apart by a distance N.

In FIGURE 4, the distribution of the uppermost nozzles `52 is such as to provide an overlapping spray pattern on `the surface of each article 18 against which the spray impinges; the distribution of the lowermost nozzles 50 provides an overlapping spray pattern on the underside surface of the articles 18 being sprayed. VIn the latter regard, the close arrangement of the conveyor rollers 48 cause the lowermost sprays, when discharged in the plane of rollers, to encounter a partial masking or blocking effeet, thus slowing down the undersurface etching rate to an appreciable extent. In case the presence of the rollers 48 combined along with other factors overcompensates for the slowness of the uppermost nozzles in their etching rate, then in that case where the rate becomes relatively excessive it `can be reduced by sliding out a retracted set of baffles 91 (FIGURE 1); the `batlies are adjustably mounted in the chamber 26 and will block off the path of spray from an appreciable number of the uppermost nozzles 52. As a means of 'keeping the blocking effect from `becoming too significant, the rollers 48 are each one beveled as indicated at S92 at the periphery to minimize its area of contact with the underside of the panel and thus stay within limits of a narrow strip path. Moreover, the rollers of alternating ones of the rows are aligned in one vertical plane only as indicated at 94 in FIGURE 3 so that their strips of contact will be staggered. The rollers in each of the remaining rows of rollers are located in a plane 96 midway (ie, N/2) between the nearest two rollers of the immediately preceding row.

The rollers 48 are plastic and are made fast at the points indicated on their respective carrying shafts `86 by means of a press fit; at their periphery they carry a set of teeth 98 which are rotated as the shaft 86 rotates. These teeth 98 are effective in the event that a warped article having a down-turned front edge tends to hang between rows of rollers; in that event, an upcoming tooth 98 would engage the down-turned leading edge at the article position 18C and raise it to the solid line position 18 of FIG- URE 5 in the plane of the tops of the rollers so as to keep the article progressing horizontally.

In FIGURES 6 and 7, each oncoming articles 1 8 entering a trap 36 encounters a full width upper roll 100 and a full width lower. roll 102 which operatively engage it Very lightly, if at all, on the topside and also on the underside, respectively. Thc upper roll 180 is capable of limited vertical movement in the direction of the fixed axis lower roll 102 and can be preloaded to a minor extent through adjustable weak springs 104 and light 4bearing blocks forming an adjustment mechanism. A full width combined bafile and wiper 106 is supported along its bottom edge and presents a lip at its free upper edge engaging the lower roll 102. The rolls and bafiies are housed in a box formed by two U-shaped channels 107 which confront one another across the path of movement of the articles 18 to form a box; the bafiie 106 is approximately in the vertical plane 108 of the adjacent division wall which supports the trap 36.

A drain tube 110 communicates with the chamber at one side of said plane 108 for returning liquid wiped by the rolls and 102 for re-collection in that chamber. A similar drain 112 establishes communication with the chamber at the opposite side of the plane 108 for returning liquid that splashes into the channels 107 so as to make it available for recirculation in that chamber. The drain is omitted from the specific trap 36 within the entry housing l34 and the drain 112 is omitted from the trap 36 in the wall 40 on the exit side of the final rinse chamber 30; the baille 106 is not essential in these two traps and is omitted if desired.

According to the modification of FIGURE 8, a double tiered arrangement is readily constructed using identical vertically spaced apart roller tables 142 to define two horizontal parallel paths instead of one through the spray etching machine.A The capacity is twice the capacity of the machine of FIGURE 1, although other than for the following exceptions, the two machines are identical.

In the spray etching chamber 126 in FIGURE 8, the lowermost group of up-turned nozzles is indicated at 150, the uppermost group of down-turned nozzles is indicated at 152, and the center group 151 is arranged to spray simultaneously upwardly and downwardly.

Traps 136 are located in accordance with the previous embodiment and the first rinse chamber 128 contains a lowermost set of nozzles 166, an uppermost set of nozzles 168 together with an upwardly and downwardly spraying set of nozzles 167 disposed between the two conveyor tables 142. The final rinse chamber 130 is separated by a division wall 139 from the first rinse chamber 128 and has an end wall 140; the chamber 130 contains a lowermost set of nozzles 172, and an uppermost set of nozzles 174 together with a set of upwardly and downwardly spraying nozzles 173.

The uppermost one of the conveyors 142 can be extended at one end beyond the corresponding end of the other conveyor 142 at the end unloading station in case the finished articles from the two paths are desired to be kept separated.

Following is an example of the specifications, dimen- Over-al1 length of machine 134 inches.

Over-all height 52 inches. Nozzle pressure uppermost nozzles 52 7 p.s.i. Nozzle pressure lowermost nozzles 50 l0 p.s.i. Discharge pressurepumps 56 13 p.s.i. Number of Washer (rinse) sections Shafts 82a, 82h and 86 titanium. Walls of chambers 26, 28

and 30 polyvinyl chloride. Etching capacity 225 square feet per hour. (Double tiered) 450 square feet per hour. Sump capacity in chamber 26-. 40 gallons. Sump temperature 130 F. (ferrie chloride). Teeth 98 on each roller 48. l0 teeth. Roller 48 diameter 7s". Roller distribution dimension N l inch to 4 inches. Roller distribution dimension M 1 inch to 4 inches. Combined baffle and Wiper 106 plasticizedpolyvinyl chloride strip 1ALG thick. Maximum Width of Work to be etched 22 inches.

Variations within the spirit and scope of the invention described are equally comprehended by the foregoing description.

We claim:

1. In a spray etcher having an end loading station and an end unloading station, the combination of spray chambers intermediate said stations and provided with liquid spraying devices therein, said spray chambers comprising etchant spray chamber means in which pressure-induced sprays of liquid etchant are confined and adjacent rinse chamber means in which pressure-induced sprays of a rinse liquid are confined, means for supporting panels to be etched comprising a horizontal roller table extending from one end station to the other for conveying panels in a path through said .spray chambers, drive means connected ttor simultaneously rotating the rollers of said table, iirst and second box-shaped trap means carried respectively at the path entry points of said etch-ant spray chamber means and said rinse chamber means and third and fourth box-shaped trap means carried respectively at the path exit points of said etchant spray chamber means and said rinse chamber means, said second and third boxshaped trap means consisting of portions of the same liquid-blocking trap located at a point in a division Wall between the chambers, and containing an upper and a lower roll in engagement with the entering and exiting panels for blocking the escape of liquid being sprayed on panels in said chambers, and a pair of drain openings disposed one on each side of the rolls in said liquidblocking trap and each communicating with the chamber at that side for returning trapped liquid thereto for recirculation.

2. In a spray etcher, means in the path of a series of horizontal panels being conveyed therethrough comprising spray chambers in tandem but divi-ded from one another, said spray chambers each provided with spraying means therein and together having a box-shaped trap vat the point of a division wall between same, a full width upper and a full width -roll in said trap operatively engageable with a panel passing therethrough, a balile wall in said box-shaped tr-ap substantially in the plane iof said division Wall and wipingly engaging one of said rolls for Substantially the full dimension of said roll, and drain openings in the trap disposed one on each side of said baf- -ile wall and each communicating with the chamber on that side for returning liquid thereto for recirculation.

3. In a panel spray etcher having an end loadin-g station and an end unloading station, means for movingly supporting panels to be etched comprising a horizontal roller table extending lfrom one end station to the other for conveying panels in a fiat path therebetween, chamber means `surrounding -a portion of said path, and cornprising vertically spaced apart groups tof etchant spray nozzles disposed .transversely to said path Within the chamber means `for spraying panels on the top side and underside surfaces simultaneously, the lowermost group of nozzles discharging upwardly through the plane of the table so Ias to irnpinge etchant on the confronting underside surface of said panels, means connected yfor rotating the rollers of said table in unison, comprising drive means disposed -on at least one longitudinal side of said table, power delivery means rfor applying power to drive said drive means, there being a plurality of said table rollers, and shafts disposed transversely in said table and carrying said plurality of table rollers yfast thereto, said shafts connected to said drive means for rotating said rollers in unison all 4at the same speed as aforesaid and under positive drive, said rollers being provided with a set of teeth in the periphery of each and dentally engageable with the leading edge of any advancing panel having a downturned Vfront edge to insure raising `ot said edge at least to the plane of the tops of the rollers.

4. In .a panel spray etcher having an end loading station and an end unloading station, means for movingly supporting panels to be etched comprising a horizontal roller table extending Ifrom one end station to the other for conveying panels in a flat path therebetween, spray chamber means surrounding a portion of said path for spraying panels on the topsi-de and underside surfaces simultaneously, and a power drive connected for simultaneously rotating the rollers of said table comprising Walking beam means disposed one on each longitudinal side of said table, power delivery means flor applying power Ito drive said Walking beam means in an endless closed path, and crank carrying shafts disposed transversely in lsaid table and each carrying a plurality of the table rollers fast thereto and connected through the crank thereof to one of said Walking beam means for rotating said rollers under positive drive, .said rollers being notched to provide a set of teeth in the periphery of each and dentally eng'ageable with Ithe leading edge of any adv-ancing panel having a downturned front edge to insure raising of the said edge at least to the plane of the tops of the rollers.

References Cited in the iile of this patent UNITED STATES PATENTS 83,389 Johnson Oct. 27, 1868 799,916 Meyer Sept. 19, 1905 899,440 Shuman Sept. 22, 1908 1,609,474 Jacobson Dec. 7, 1926 2,124,008 Roth July 19, 1938 2,240,809 Simonds May 6, 1941 2,264,885 Mueller Dec. 2, 1941 2,634,449 Kuljian Apr. 14, 1953 2,701,049 Kendall Feb. 1, 1955 2,733,805 Lyman Feb. 7, 1956 UNITED STATES PATENT oEETCE CERTIFICATE 0E CORRECTION Patent No. 3108.2774 March 26F 1963 Robert C., Benton et al.

It s hereby certified that error appears 1n the above numbered patent reqlrng correction and that the said Letters Patent should read as corrected below.

after "width" insert lower Column 5T line 70."

Signed and sealed this Ist day of Octobe (SEAL) Attest:

ERNEST Wo SWIDER DAVID L. LADD 

1. IN A SPRAY ETCHER HAVING AN END LOADING STATION AND AN END UNLOADING STATION, THE COMBINATION OF SPRAY CHAMBERS INTERMEDIATE SAID STATIONS AND PROVIDED WITH LIQUID SPRAYING DEVICES THEREIN, SAID SPRAY CHAMBERS COMPRISING ETCHANT SPRAY CHAMBER MEANS IN WHICH PRESSURE-INDUCED SPRAYS OF LIQUID ETCHANT ARE CONFINED AND ADJACENT RINSE CHAMBER MEANS IN WHICH PRESSURE-INDUCED SPRAYS OF A RINSE LIQUID ARE CONFINED, MEANS FOR SUPPORTING PANELS TO BE ETCHED COMPRISING A HORIZONTAL ROLLER TABLE EXTENDING FROM ONE END STATION TO THE OTHER FOR CONVEYING PANELS IN A PATH THROUGH SAID SPRAY CHAMBERS, DRIVE MEANS CONNECTED FOR SIMULTANEOUSLY ROTATING THE ROLLERS OF SAID TABLE, FIRST AND SECOND BOX-SHAPED TRAP MEANS CARRIED RESPECTIVELY AT THE PATH ENTRY POINTS OF SAID ETCHANT SPRAY CHAMBER MEANS AND SAID RINSE CHAMBER MEANS AND THIRD AND FOURTH BOX-SHAPED TRAP MEANS CARRIED RESPECTIVELY AT THE PATH EXIT POINTS OF SAID ETCHANT SPRAY CHAMBER MEANS AND SAID RINSE CHAMBER MEANS, SAID SECOND AND THIRD BOXSHAPED TRAP MEANS CONSISTING OF PORTIONS OF THE SAME LIQUID-BLOCKING TRAP LOCATED AT A POINT IN A DIVISION WALL BETWEEN THE CHAMBERS, AND CONTAINING AN UPPER AND A LOWER ROLL IN ENGAGEMENT WITH THE ENTERING AND EXITING PANELS FOR BLOCKING THE ESCAPE OF LIQUID BEING SPRAYED ON PANELS IN SAID CHAMBERS, AND A PAIR OF DRAIN OPENINGS DISPOSED ONE ON EACH SIDE OF THE ROLLS IN SAID LIQUIDBLOCKING TRAP AND EACH COMMUNICATING WITH THE CHAMBER AT THAT SIDE FOR RETURNING TRAPPED LIQUID THERETO FOR RECIRCULATION. 